- Question
How do drugs affect the brain?
A psychoactive drug is a chemical substance which, when consumed, can affect the brain and nervous system, resulting in an altered mental state. The potent effects of psychoactive drugs have led some to be used as prescription medicines, while others have become some of the most widely prohibited illicit substances in the world. So what are the effects of drugs on the brain? What are the different types of psychoactive drug, and how do these various chemicals affect behaviour, consciousness, mood, perception, and the functioning of the brain?
Hallucinogens alter perception and cause hallucinations
Hallucinogenic substances interact with receptor molecules in the brain, including acetylcholine, glutamate, and serotonin receptors, with a range of effects from perceptual changes to hallucinatory experiences.
Depressants slow brain and nervous system function
This position explains how depressant drugs affect the brain by slowing the nervous system. It argues depressants inhibit neural signals and reduce brain activity—covering substances such as alcohol, opioid painkillers, and sedative-hypnotics that relieve anxiety and promote sleep.
Stimulants elevate alertness and mood
Stimulant drugs affect the brain's internal communication and transmission processes, often targeting the dopamine reward pathway to cause feelings of euphoria.